Many and varied types of valving mechanisms have been heretofore proposed for sealing a line through which fluid flows against the reverse flow of the fluids. However, such valves are not usable in all planes in which they are disposed, such as, horizontal, vertical or angular planes. Furthermore, such valves are not self centering and require guides or hinges for centering purposes. At times despite the presence of such guides and hinges, the valve does not attain the identical sealing location in each operation. Many such valves are noisy in operation and are of such construction that particulates of solid material accumulate on the sealing surface.
In addition other valve mechanisms are not adapted to function for other purposes such as a vacuum breaker or a foot valve.